Attention recently has been directed to implementing a variety of communication services, including voice telephone service, over the worldwide packet data network now commonly known as the Internet. The Internet had its genesis in U.S. Government programs funded by the Advanced Research Projects Agency (ARPA). That research made possible national internetworked data communication systems. This work resulted in the development of network standards as well as a set of conventions, known as protocols, for interconnecting data networks and routing information across the networks. These protocols are commonly referred to as TCP/IP. The TCP/IP protocols were originally developed for use only through ARPANET but have subsequently become widely used in the industry. TCP/IP is flexible and robust. TCP takes care of the integrity, and IP moves the data.
Internet provides two broad types of services: connectionless packet delivery service and reliable stream transport service. The Internet basically comprises several large computer networks joined together over high-speed data links ranging from ISDN to T1, T3, FDDI, SONET, SMDS, ATM, OT1, etc. The most prominent of these national nets are MILNET (Military Network), NSFNET (National Science Foundation NETwork), and CREN (Corporation for Research and Educational Networking). In 1995, the Government Accounting Office (GAO) reported that the Internet linked 59,000 networks, 2.2 million computers and 15 million users in 92 countries. However, since then it is estimated that the number of Internet users continues to double approximately annually.
In simplified fashion the Internet may be viewed as a series of packet data switches or `routers` connected together with computers connected to the routers. The Information Providers (IPs) constitute the end systems which collect and market the information through their own servers. Access providers are companies such as UUNET, PSI, MCI and SPRINT which transport the information. Such companies market the usage of their networks.
FIG. 5 shows a simplified diagram of the Internet and various types of systems typically connected thereto. Generally speaking the Internet consists of Autonomous Systems (AS) type packet data networks which may be owned and operated by Internet Service Providers (ISPs) such as PSI, UUNET, MCI, SPRINT, etc. Three such AS/ISPs appear in FIG. 5 at 310, 312 and 314. The Autonomous Systems (ASs) are linked by Inter-AS Connections 311, 313 and 315. Information Providers (IPs) 316 and 318, such as America Online (AOL) and Compuserve, connect to the Internet via high speed lines 320 and 322, such as T1/T3 and the like. Information Providers generally do not have their own Internet based Autonomous Systems but have or use Dial-Up Networks such as SprintNet (X.25), DATAPAC and TYMNET.
By way of current illustration, MCI is both an ISP and an IP, SPRINT is an ISP, and the MicroSoft Network (MSN) is an IP using UUNET as an ISP. Other information providers, such as universities, are indicated in exemplary fashion at 324 and are connected to the AS/ISPs via the same type connections here illustrated as T1 lines 326. Corporate Local Area Networks (LANs), such as those illustrated in 328 and 330, are connected through routers 332 and 334 and high speed data links such as T1 lines 336 and 338. Laptop computers 340 and 342 are representative of computers connected to the Internet via the public switched telephone network (PSTN) and are shown connected to the AS/ISPs via dial up links 344 and 346.
In the addressing scheme of the Internet, an address comprises four numbers separated by dots. This is called the Internet Protocol address, or IP address. An example of an IP address would be 164.109.211.237. Each machine on the Internet has a unique number assigned to it which constitutes one of these four numbers. In the IP address, the leftmost number has the greatest weight. By analogy this would correspond to the ZIP code in a mailing address. At times the first two numbers constitute this portion of the address indicating a network or a locale. That network is connected to the last router in the transport path. In differentiating between two computers in the same destination network only the last number field changes. In such an example the next number field 211 identifies the destination router.
When a packet bearing a destination address leaves the source router, the router examines the first two numbers in a matrix table to determine how many hops are the minimum to get to the destination. It then sends the packet to the next router as determined from that table, and the procedure is repeated. Each router has a database table that finds the information automatically. This continues until the packet arrives at the destination computer. The separate packets that constitute a message may not travel the same path depending on traffic load. However, they all reach the same destination and are assembled in their original order in a connectionless fashion. This is in contrast to connection oriented routing modes, such as frame relay and ATM or voice.
It would be difficult for most people to remember the four separate numbers (sometimes having ten or more digits) comprising each numeric IP address. In addition numeric IP addresses occasionally change, making it even more of a problem for people to keep track of them. The Domain Name System (DNS) was developed to provide some relief from these problems. In the DNS system words, which are more easily remembered, are used instead of numbers.
An example of a textual Domain Name is Evoit@HUT.MB.COM. Each of the names separated by a dot is called a domain. The significance of each of the domains is the reverse of that of the numeric IP address. In the numeric IP address, the most significant numbers were on the left and the least significant on the right. The textual Domain Name System begins with the least significant on the left and proceeds to the most significant on the right.
The top-level domains, those of the most general significance, are as follows:
1. COM A commercial operation PA1 2. EDU A university, college or other educational institution PA1 3. GOV A government organization PA1 4. MIL A military site PA1 5. ORG Any organization that does not fit into any of the preceding PA1 6. NET A network
There are now two-letter domains, each denoting a different country, which are atop the above original domain names. An address ending in "COM.AU," for example, would be a commercial operation in Australia. Over a hundred different countries are now connected to the Internet so the list of two-letter country codes is long and getting longer. Computers associated with the Internet called domain name servers convert textual domain names into numeric IP addresses.
The domain name processing by the domain name servers has always involved only a straight translation from the domain name to a single IP address. The domain name servers have not offered any type of customized processing or control to meet individual needs of parties identified by domain name addresses.
Recently, one or more companies have developed software for use on personal computers to permit two-way transfer of real-time voice information via an Internet data link between two personal computers. In one of the directions, the sending computer converts voice signals from analog to digital format. The software facilitates data compression down to a rate compatible with modem communication via a POTS telephone line, in some cases as low as 2.4 kbits/s. The software also facilitates encapsulation of the digitized and compressed voice data into the TCP/IP protocol, with appropriate addressing to permit communication via the Internet. At the receiving end, the computer and software reverse the process to recover the analog voice information for presentation to the other party. Such programs permit telephone-like communication between Internet users registered with Internet Phone Servers.
Such programs have relied on servers coupled to the Internet to establish voice communication links through the networks. Each person active on the network, who is willing to accept a voice call, must register with a server. A calling party can call only those persons registered on the voice communication server. Also, the address management provided by these servers, like that provided by the domain name servers, has not permitted any individualized control of routing. For example, a user could register only one current address and must reregister each time the user comes on-line with a new address. The registration server provides no automatic selection of alternate destinations.
Concurrent with recent developments in public packet data communications such as the Internet, outlined above, the telephone industry has been developing an enhanced telephone network, sometimes referred to as an Advanced Intelligent Network (AIN), for providing a wide array of new voice grade telephone service features. In an AIN type system, local and/or toll offices of the public telephone network detect one of a number of call processing events identified as AIN "triggers". For ordinary telephone service calls, there would be no event to trigger AIN processing; and the local and toll office switches would function normally and process such calls without referring to the central database for instructions. An office which detects a trigger will suspend call processing, compile a call data message and forward that message via a common channel interoffice signaling (CCIS) link to a database system, such as an Integrated Service Control Point (ISCP) which includes a Multi-Services Application Platform (MSAP) database. If needed, the ISCP can instruct the central office to obtain and forward additional information. Once sufficient information about the call has reached the ISCP, the ISCP accesses its stored data tables in the MSAP database to translate the received message data into a call control message and returns the call control message to the office of the network via CCIS link. The network offices then use the call control message to complete the particular call. An AIN type network for providing an Area Wide Centrex service, for example, was disclosed and described in detail in commonly assigned U.S. Pat. No. 5,247,571 to Kay et al., the disclosure of which is entirely incorporated herein by reference.
As shown by the art discussed above, the Internet and the AIN have remained separate, independent areas of technical development. Many telephone service subscribers are accustomed to enhanced telephone features, such as those provided by AIN processing. However, the wide range of conditional routing options offered by AIN type processing have simply not been available on the Internet. For example, the address processing provided by the domain name servers and the registration servers used to exchange addresses for voice communication have not permitted alternate treatments for different times, different calling parties, different destinations of roaming subscribers, etc.
As use of the Internet expands, particularly for transport of voice telephone communications, a need exists for enhanced address management that will facilitate advanced routing features through the public packet data network to offer customers using that network service features similar to those commonly available via the AIN and other advanced telephone networks.